Low resistance terminal connector for air-depolarized cathode

ABSTRACT

1. An air-depolarized primary battery comprising an electrolyte solution, an anode in said solution, a carbon cathode partially immersed in said solution and having a plurality of vertical cavities therein extending through the top face thereof to the bottom portion thereof, said cavities being cylindrically shaped, a helix wire of a conductive spring material inserted in each of said cavities throughout the length thereof, each of said wire helices having normally a larger outside diameter than the diameter of said respective cavity causing the wire helix to exert a radial pressure against the wall of the cavity and provide a continuous firm engagement of the helix on a helical line with said cathode, a terminal post anchored into an upper portion of said cathode between said cavities in electrically conductive relationship with the cathode, a lead wire extending from and electrically connected to each of said wire helices, and means electrically connecting each of said lead wires to said terminal post.

J. E. SCHMIDT 3,843,413

LOW RESISTKNCE TERMINAL CONNECTOR FOR AIR-DEPOLARIZED CATHODE- Oct. 22,1974 2 Sheets-Sheet 1 Filed Oct. 50, 1972 J. E. SCHMIDT Oct. 22, 1974LOW RESISTANCE TERMINAL commcwon FOR AIR-DEPOLARIZED canons 2Sheets-Sheet 2 Filed Oct. 50, 1972 FIG. 2

l l/llll United States Patent 3,843,413 LOW RESISTANCE TERMINALCONNECTOR FOR AlR-DEPOLARIZED CATHODE Jacob E. Schmidt, Little FallsTownship, Passaic County, N.J., assignor to McGraw-Edisou Company,Elgin, 11]. Filed Oct. 30, 1972, Ser. No. 301,870 Int. Cl. H01m 29/02U.S. Cl. 136-86 A 1 Claim ABSTRACT OF THE DISCLOSURE An air-depolarizedbattery of the type having a carbon cathode with one or more cavitiesleading through the top face to a lower portion thereof is provided witha wire coil in each cavity which is inserted under tension so that whenreleased it springs out to engage the cavity wall under pressure. Thecoil provides a low resistance connection continuously throughout theheight of the cathode from the lower portions closed to the activeinterface of the cathode with the electrolyte to the upper portionengaged by the cathode terminal. Preferably, the coil has also an uppertail extension connected to the cathode terminal for providing a directconnection of the terminal with each such lower portion of the cathode.

An object of the invention is to provide an air-depolarized batteryhaving increased efiiciency and greater ampere output.

Another object is to provide an improved low-resistance terminalconnection to an air-depolarized cathode.

A further object is to provide a novel electrode connection to anair-depolarized cathode which is continuous throughout the height of thecathode and in proximity with the interface between the cathode and theelecrolyte.

These and other objects and features of the invention will be apparentfrom the following description and the appended claims.

FIG. 1 is a vertical section on a medial plane through anair-depolarized battery incorporating the invention; and

FIG. 2 is a vertical section on the line 2-2 of FIG. 1.

The battery illustrated in the accompanying drawings has a rectangularcase as of acrylic plastic material comprising a lower rectangularcontainer 11 and a cover 12 seated on and sealed to the rim of thecontainer. The cover has depending flanges 13 receiving plastic holders14 in sealed relation thereto for a pair of spaced zinc anodes 15, andhas a carbon cathode 16 spaced midway between the zinc anodes. Thecarbon cathode is supported from the cover 12 by a plastic hanger 35 andis sealed along its rim to the cover by a suitable sealing compound 36such as of pitch. An opening 17 in the cover inset from the rim of thecathode exposes the top face of the cathode to a rectangular aircompartment 18 bounded by side and end walls 19 and 20 upstanding fromthe cover and by a top cover plate 21. In the end walls 20 there areopenings 22 to the atmosphere and on the top cover plate 21 there arestacks 23 with side openings 24 to the atmosphere. These openings permita passage of air from the atmosphere through the air compartment intodirect contact with the carbon cathode 16.

The carbon cathode is provided with one or more cavities 25four beingshown by way of example-which extend through the top face of the cathodedownwardly to the bottom portion thereof so as to permit a flow of airto portions of the cathode close to the interface thereof with theelectrolyte. Additionally, the battery is desirably provided wih achimney system as is described in my copending application filed July17, 1972 and entitled Airdepolarized Primary Battery, to augment theflow of air ice from the outside atmosphere to the bottom portions ofthe cavities. However, such chimney system need not necessarily beemployed with the present invention and is not herein described.

The present invention takes advantage of the provision of the aircavities in air-depolarizing cathode electrodes to obtain alow-resistance electrical connection with the cathode whereby a markedlyhigher voltage and ampere output are obtained from the battery. This isaccomplished by inserting a wire coil 26 into each cavity from thebottom portion thereof to the top thereof. The coil is made of lowresistance wire such as of copper, but whatever material is used isdesirably also of a springy character so that the coil will engage thewall of each cavity under pressure. For this purpose each coil is madeto have a normal outside diameter suitably larger than the diameter ofthe cavity into which it is to be placed, and the coil is tensioned orwound inwardly on itself to reduce its outside diameter so that it canbe readily inserted into the cavity. After the coil is inserted it isreleased to spring outwardly and engage the wall of the cavity underpressure on a continuous helical line from the bottom portion of thecathode to thetop thereof.

The provision of such coil in each cavity has the advantage that itprovides a low resistance direct connection continuously throughout theheight of the cathode to the portion of the cathode surrounding eachcavity to reduce the resistance to current flow from each portion of thecathode having an interface with the electrolyte to the upper portion ofthe cathode engaged by the terminal of the battery. To reduce stillfurther the resistance to current flow from the active portions of thebattery having an interface with the electrolyte to the cathode terminaleach wire coil is provided wih an extending tail 26 at its upper endwhich is led across the top of the carbon cathode to the center of thebattery whereat it is soldered to an apertured lug 28 of a washer 29. Aterminal post 30 for the cathode is extended through the top cover plate21 and sealed thereto by clamping pressure of a nut 31 threaded onto thepost to exert pressure through a sealing washer 32 onto the surroundingportion of the top plate 21 backed by a stop nut 33 on the post. Theterminal post 30 then extends further through the washer 29 and into theupper part of the cathode. Above the washer 29 there is a pair of nuts34 tightened to clamp the washer against the upper face of the carboncathode with the upper nut being tightened against the lower one in alocking relationship. Thus, a metallic low-resistance connection isobtained between the terminal post and every portion of the cathode inclose electrical contact with the electrolyte. This metallic connectorof the terminal post continuously throughout the height of the cathodewith every portion in close active relationship with the electrolytecircumvents the need for the current from the interface between thecathode and the electrolyte to flow through any substantial portion ofhigh resistance cathode material. Thus, a higher output voltage isobtained and electrical losses within the battery are reduced toincrease the amperes output of the battery.

The embodiment of my invention herein particularly shown and describedis intended to be illustrative and not necessarily limitative of myinvention, since the same is subject to changes and modificationswithout departure from the scope of my invention, which I endeavor toexpress according to the following claim.

I claim:

1. An air-depolarized primary battery comprising an electrolytesolution, an anode in said solution, a carbon cathode partially immersedin said solution and having a plurality of vertical cavities thereinextending through the top face thereof to the bottom portion thereof,said cavities being cylindrically shaped, a helix wire of aconduchviignormauy alafger outside dia'rh't'er than the' diameter ofsaid respective cavity causing the wire helix to exert a radial pressureagainst the wall of the cavity and provide a continuous firm engagementof the helix on a helical line with said cathode, a terminal postanchored into an upper portion of said cathode between said cavities inelectrically conductive relationship with the cathode, a lead wireextending from and electrically connected to each of said wire helices.and means electrically connecting each of said lead wires to saidterminal post.

References Cited UNITED STATES PATENTS 2/1964 Broers 136-86F 5/1960Kordesch .13-6--122 US. Cl. X.R.

1. An air-depolarized primary battery comprising an electrolytesolution, an anode in said solution, a carbon cathode partially immersedin said solution and having a plurality of vertical cavities thereinextending through the top face thereof to the bottom portion thereof,said cavities being cylindrically shaped, a helix wire of a conductivespring material inserted in each of said cavities throughout the lengththereof, each of said wire helices having normally a larger outsidediameter than the diameter of said respective cavity causing the wirehelix to exert a radial pressure against the wall of the cavity andprovide a continuous firm engagement of the helix on a helical line withsaid cathode, a terminal post anchored into an upper portion of saidcathode between said cavities in electrically conductive relationshipwith the cathode, a lead wire extending from and electrically connectedto each of said wire helices, and means electrically connecting each ofsaid lead wires to said terminal post.